It is known as for example from German Pat. No. 2,440,495 and from U.S. Pat. No. 4,543,810 to provide a six-high roll stand having two outer backup rolls, two inner backup rolls, and two working rolls. Such a roll stand can have a device for displacing the inner backup rolls parallel to their axes, so that the effects of bending of the rolls can be canceled out.
Such an axial-shifting device typically comprises two rigid arms projecting axially from one of the journal blocks of the roll to be shifted, and a massive hydraulic ram having an outer end pivoted about a normally horizontal axis on the stationary machine frame and an inner end pivoted about another horizontal axis on the outer ends of the arms. Such a cylinder can be expanded to move the respective roll in and contracted to move it out. The pivots are provided so that the shifting apparatus can follow any vertical movements of the roll to be shifted.
Even if such a ram is coupled to an axially slidable pusher as described in German patent document No. 3,145,134 there is a considerable radial force vector applied to the machine. Normally this lateral force is applied to the journal block and its arms. Thus whatever structure is provided to stand against this lateral force must be substantial and must also be provided with some troublesome lubrication system, as considerable movement is required.